Transcript for Stories Emerge From Passengers Who Didn't Make It Onto Flight MH17

lost so many people and bears reminding this is a human tragedy. Nearly 300 lost souls and starting to hear some of their stories and the twist of fate surrounding that doomed flight. Circumstances keeping some people off the plane saving their lives while others wound up last-minute passengers. ABC's David Wright has the incredible stories from Kuala Lumpur. David. Reporter: Good morning, bianna. Across this country, flags at half-staff, people here still grab 8ing with the disappearance of Malaysian air 370 now mourning the loss of flight 17 too and we're hearing stories today from the lucky few, ticketed passengers who ended up not getting on board that plane. Barry and izzy sim tried to fly out on mh17 but the flight was oversold. There weren't enough seats for them and their baby. I was going to change my luck to be on Malaysian airlines and we couldn't get both on the flight this morning so we changed it to the klm one. Reporter: That decision saved their lives. Just shock you get the sick feeling in the pit of your stomach. We were supposed to be on that flight and obviously, you know, something watching over us and say, no, don't get on that flight. Reporter: Australian newly wed Simone and Juan had tickets on mh17 coming home from their honeymoon. We have some pretty good guardian angels. And ended up flying home a day early worrying about getting over the jet lag for work. Feeling lucky but at the same time hard to believe for these families that, you know, expecting their loved ones to come home. Reporter: Flight attendant San Ji Singh swapped on to it in the last moment. In March his wife also a flight attendant swapped off flight 370. She lived. He's gone. Marten is lucky twice. He was booked on both flights and ended up not boarding the fateful flight. Here in Malaysia there's truly a sense that lightning has struck twice. The agony still fresh for those flight 370 families, now dozens more sharing their grief. Dan? Lightning striking twice, David Wright, thank you. This is a disaster that could change the face of commercial aviation. The flight path over eastern Ukraine was technically open for business on the day mh17 was shut down. Dozens crossed the space that day and planes regularly fly over war Zones all over this planet so could this crash change that and what kind of impact will it have on us flyers. Jim Avila is at Reagan national airport. Jim, good morning. Reporter: Good morning, Dan. We board a flight we know where we're going but we rarely think about the route the pilot is taking. For the shootdown of this passenger jet that may change. Add Ukraine to a growing list of hot spots international airlines are required to avoid. North Korea, Yemen, the sinai peninsula and Syria. A big chunk of airspace. So why did Malaysian air flight 17 pass over a combat zone Thursday? Because that area wasn't closed down above 32,000 feet and the doomed 777 was flying at an unrestricted 33,000 feet when the missile brought it down. ABC news aviation consultant John nance says it may have been flying legally but it was still flying unwise. When you're flying over a war zone it doesn't matter if somebody says, well, you're okay above 32,000 feet. Maybe you want to be more conservative. Reporter: After the missile strike all airspace over eastern Ukraine was closed. An expensive detour for airlines who lose time, about ten minutes to fly around the combat zone and $1500 per flight in fuel costs. But despite the cost in time and money, this week, the biggest aviation lesson may be more caution from regulators and pilots in times of war. We've got to be much more proactive about staying clear of any possible hot zone in terms of combat on the ground. Reporter: But in the air all those simultaneous war Zones on the ground carve out thousands of miles through a popular air corridor with some of the world's heaviest traffic. Pilots, passengers and airlines thinking a lot more about what's below us as we fly in the air. Dan. Thinking a lot more about that flight path. All right, Jim, thank you. That concludes our coverage this morning of Malaysian flight 17 and we'll continue with all breaking news and top developments on ABC news and abcnews.com but turn to the

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